The present invention is related to a radiation image photographing apparatus, and in particular, to a radiation image photographing apparatus for taking a radiation image for diagnosing deformation of joints.
Heretofore, an examinee has needed to be fixed in the course of taking a radiation image, and, for example, there is known an apparatus to press and fix an abdominal region of an examinee with an air pillow when radiographing a digestive organ which is shown in Patent Document 1. Further, in the case of a breast-radiographing apparatus, a compression board is usually used to fix a subject on a subject table.
As shown in FIG. 13, the breast-radiographing apparatus 50 of this kind is provided with radiation source 51 that irradiates radiation toward subject H, detector holding device 52 that holds a radiation image detector detecting radiation that is emitted from radiation source 51 and is transmitted through subject H, and with subject table 53 that is arranged between the radiation source 51 and the detector holding device 52 to hold the subject H. These constituting structures are provided vertically, so that an examinee may be radiographed while keeping an upright posture.
There is further known a radiation image photographing apparatus to take a phase contrast image for improving sufficiently the contrast of a radiation image to be obtained (for example, see Patent Document 2). When taking a phase contrast image, it is necessary to provide a distance in prescribed quantity between radiation source 51 and a subject and between a subject and a radiation image detector. The phase contrast photographing of this kind is one of magnification techniques.
Now, a rheumatism disease is given as one of diseases appearing on the limbs. The rheumatism disease includes a symptom appearing on a bone region such as osteoporosis and a symptom appearing on a cartilage region such as cartilage destruction. Since these symptoms appear earliest on a cartilage region of the limbs, images obtained through photographing of a cartilage of fingers by MRI have been used for diagnoses. However, the photographing by MRI causes a heavy burden for an examinee from the viewpoint of expenses and time required for diagnoses, resulting in a problem that periodical photographing and observation of changes in a cartilage of fingers are difficult.
Recently, therefore, the inventors of the present invention has suggested a technology which can capture images of cartilage portions which are highly visible through taking phase contrast images by using a X-ray photographing apparatus, even in the case where X-ray absorbing difference is small as in the space between the cartilage region and its periphery. The invention in this case provides a radiation image photographing apparatus that generates highly visible images of a joint region including a cartilage region.
In the radiation image photographing apparatus of the invention, it is possible to radiograph periodically a joint region of fingers of an examinee, and thereby, it is easy to conduct observation diagnoses for presence or absence of aging changes of cartilage of a joint region (for example, wearing-off of a cartilage region or the like), thus, it is possible to subdue disease spreading by early detection of rheumatism diseases and by early medical treatment for patients.
In conventional radiation image photographing apparatus 50, there has been a problem that detector holding device 52 is protruded toward the examinee side from an edge of subject table 53, thereby, a posture to approach the subject table 53 cannot be taken and the arm of the examinee is not stabilized, making it difficult to fix fingers. However, the radiation image photographing apparatus of the present invention makes it possible to solve the aforesaid problem. Therefore, even if an examinee is relatively old in terms of an age, motion artifact of the arm is hardly caused, and it is easy to radiograph without movement of fingers, which does not force a burden on the examinee. Further, even if an extent of opening and the direction of fingers of the examinee are different in each radiographing, an irradiation angle of radiation for the subject can be made constant, thereby, it is possible to detect aging changes by comparison of finger radiographic images, even if the aging changes are slight.
[Patent Document 1] Japanese Patent Publication Open to Public Inspection No. 2005-40505
[Patent Document 2] Japanese Patent Publication Open to Public Inspection No. 2004-173879